29 September 1997 – Subject To Change
Hardware Interface
3–5
21164PC Signal Names and Functions
clk_mode_h<1:0>
I
2
Clock test mode. These signals specify a relationship between
osc_clk_in_h,l, the CPU cycle time, and the duty-cycle equal-
izer. These signals should be deasserted in normal operation
mode.
Table 3–1 21164PC Signal Descriptions
(Sheet 2 of 10)
Signal
Type Count Description
Bits Description
00
CPU clock frequency is equal to the input clock fre-
quency.
01
CPU clock frequency is equal to the input clock fre-
quency, with the onchip duty-cycle equalizer enabled.
10
Initialize the CPU clock, allowing the system clock to be
synchronized to a stable reference clock.
11
Initialize the CPU clock, allowing the system clock to be
synchronized to a stable reference clock, with the onchip
duty-cycle equalizer enabled.